A subordinate clause — une proposition subordonnée — is a clause that depends on a main clause and cannot stand on its own as a complete sentence. Je sais qu'il vient (I know that he is coming) contains a main clause je sais and a subordinate clause qu'il vient. The subordinate clause is anchored by the conjunction que, and removing the main clause leaves us with a fragment: qu'il vient is not a sentence on its own.
This contrasts with coordination (covered in the previous page), where two clauses are linked as equals. Pierre travaille et Marie étudie — both halves can stand alone. In subordination, one clause is the host, the other a guest; remove the host and the guest collapses.
This page is the gateway to French complex sentence syntax. It surveys the main subordinator words, classifies the major types of subordinate clauses, and introduces the central question that complex sentences raise: which mood does the subordinate verb take? The answer — indicative, subjunctive, or conditional — depends on the meaning of the main clause and the conjunction that links them. Each major type has its own dedicated page; this overview shows the lay of the land.
What is a subordinate clause?
A subordinate clause has three parts:
- A subordinator — a conjunction or relative pronoun that introduces the clause (que, qui, quand, parce que, si, pour que, bien que).
- A subject (sometimes elided in non-finite forms).
- A verb in some mood and tense.
The subordinator does double duty: it identifies the clause as subordinate, and it defines the relationship between the two clauses (cause, time, purpose, condition, complement, etc.).
Je dis que tu viens.
I say that you're coming.
L'homme qui parle est mon père.
The man who is speaking is my father.
Quand il vient, on mangera.
When he comes, we'll eat.
In each example, the subordinate clause is in a fixed grammatical relationship with the main clause: que tu viens completes dis (it's the object of saying); qui parle modifies l'homme (it's adjectival); quand il vient sets the time for on mangera (it's adverbial).
Major types of subordinate clauses
French distinguishes three broad categories of subordinate clauses, by their function:
1. Completive clauses (complement clauses)
A completive clause functions as the object or subject of the main verb. It is almost always introduced by que and answers the question what?.
Je dis que tu viens.
I say that you're coming.
Je sais qu'il pleut.
I know that it's raining.
Je veux que tu partes.
I want you to leave.
Il faut que nous fassions attention.
We need to be careful.
The choice of mood in the completive clause depends on the main verb:
- Verbs of statement and knowledge (dire, savoir, penser, croire) → indicative.
- Verbs of will, emotion, doubt (vouloir, aimer, douter, avoir peur) → subjunctive.
This indicative-vs-subjunctive split is one of the central facts of French grammar and gets its own dedicated treatment in the verbs/subjunctive cluster. The slogan: indicative for what is or is asserted; subjunctive for what is wished, doubted, or felt.
2. Relative clauses
A relative clause modifies a noun (l'homme qui parle — the man who is speaking). It functions like an adjective, attaching to a noun phrase to add information. Relative clauses are introduced by relative pronouns — qui, que, dont, où, lequel, etc.
L'homme qui parle est mon père.
The man who is speaking is my father.
Le livre que je lis est passionnant.
The book that I'm reading is fascinating.
La ville où je suis né est petite.
The city where I was born is small.
L'ami dont je t'ai parlé arrive demain.
The friend I told you about is arriving tomorrow.
The choice between qui and que depends on the role the relative pronoun plays inside the relative clause:
- qui = subject of the relative clause (l'homme *qui parle — the man *who speaks; qui is the subject of parle).
- que = direct object of the relative clause (le livre *que je lis — the book *that I read; que is the object of lis).
This subject/object distinction is rigid in French and one of the most common error sources for English speakers, since English uses that for both functions.
3. Adverbial (circumstantial) clauses
An adverbial clause modifies the main verb the way an adverb would, situating the action in time, cause, condition, purpose, concession, manner, etc. They are introduced by a wide variety of subordinating conjunctions.
| Conjunction | Relationship | Example |
|---|---|---|
| quand, lorsque | time | Quand il vient, on mange. |
| parce que | cause | Je reste parce qu'il pleut. |
| pour que, afin que | purpose | Je parle fort pour que tu m'entendes. |
| bien que, quoique | concession | Bien qu'il pleuve, je sors. |
| si | condition | Si tu viens, on parlera. |
| avant que | anteriority | Pars avant qu'il arrive. |
| après que | posteriority | On mangera après qu'il sera parti. |
| comme, puisque | given cause | Puisque tu insistes, j'accepte. |
| tandis que, alors que | contrast | Pierre travaille tandis que Marie joue. |
Quand il vient, on mangera ensemble.
When he comes, we'll eat together.
Je reste parce qu'il pleut.
I'm staying because it's raining.
Je parle fort pour qu'il m'entende.
I'm speaking loudly so that he hears me.
Bien qu'il pleuve, je vais sortir.
Although it's raining, I'm going to go out.
Each of these conjunctions has its own dedicated page in the complex/ cluster (cause, time, purpose, concession, condition). The summary table at complex/clauses-overview-table puts them all side by side with their mood requirements.
Mood selection in subordinate clauses
The single most important question in French complex syntax: which mood does the subordinate verb take? French has three main moods that compete for the subordinate slot — indicative, subjunctive, and conditional — and the choice is governed by a system of triggers in the main clause and the conjunction.
Indicative (the default)
The indicative is the mood of asserted reality. Most subordinate clauses use the indicative because most subordinate clauses describe something the speaker takes as a fact or established information.
Je sais qu'il vient.
I know that he's coming. (indicative, fact)
Je dis qu'elle a raison.
I'm saying that she's right.
Quand il pleut, je reste à la maison.
When it rains, I stay home.
Parce qu'il pleut, on annule la sortie.
Because it's raining, we're cancelling the outing.
After verbs of knowledge (savoir, connaître), assertion (dire, affirmer, déclarer), perception (voir, entendre, constater), and after most adverbial conjunctions of time, cause, and consequence, the indicative is the rule.
Subjunctive (volition, emotion, doubt, certain conjunctions)
The subjunctive is the mood of the unrealized — wishes, doubts, possibilities, things hoped or feared but not asserted as fact. It is triggered by:
- Main verbs of will and desire (vouloir que, souhaiter que, aimer que).
- Main verbs of emotion (être content que, avoir peur que, regretter que).
- Main verbs of doubt and denial (douter que, ne pas penser que, ne pas croire que).
- Impersonal expressions of necessity, possibility, or judgment (il faut que, il est possible que, il vaut mieux que).
- Specific conjunctions of purpose (pour que, afin que), concession (bien que, quoique), anteriority (avant que), and condition (à condition que, à moins que, pourvu que).
Je veux qu'il vienne.
I want him to come. (subjunctive after verb of will)
Je suis content que tu sois là.
I'm glad you're here. (subjunctive after emotion)
Je doute qu'il vienne.
I doubt he'll come. (subjunctive after doubt)
Il faut qu'on parte.
We have to leave. (subjunctive after impersonal necessity)
Bien qu'il pleuve, je sors.
Although it's raining, I'm going out. (subjunctive after concession)
Pars avant qu'il arrive.
Leave before he arrives. (subjunctive after avant que)
The deep logic: the subjunctive marks an action that exists in the realm of wishes, doubts, possibilities, and conditions rather than established reality. Je veux qu'il vienne means I want his coming to become true — not a fact, but a desired state. Bien qu'il pleuve presents the rain as a backdrop concession, not as the focus of assertion. Once you internalize this principle, you can predict subjunctive use even in sentences you have never seen.
For full coverage of subjunctive triggers and forms, see the verbs/subjunctive cluster and especially the trigger-by-trigger pages.
Conditional (in si-clause hypotheticals)
The conditional is reserved for hypothetical situations, especially in the structure si + clause + main clause with conditional. The pattern is:
| If-clause (the si) | Main clause | Meaning |
|---|---|---|
| si + present | future / present | possible (real condition) |
| si + imparfait | conditional present | hypothetical (unlikely or counterfactual) |
| si + plus-que-parfait | conditional past | past counterfactual |
Si tu viens, on parlera.
If you come, we'll talk. (real condition: si + present, future main)
Si tu venais, on parlerait.
If you came, we would talk. (hypothetical: si + imparfait, conditional main)
Si tu étais venu, on aurait parlé.
If you had come, we would have talked. (counterfactual: si + plus-que-parfait, conditional past main)
A critical rule: never use the conditional or subjunctive directly after si in a hypothetical construction. The si clause itself takes indicative (present, imparfait, or plus-que-parfait depending on the type), and the conditional appears in the main clause. Si je serais riche is wrong; si j'étais riche, je serais heureux is right.
For deeper coverage, see the complex/conditional-sentences-overview and complex/hypothetical-conditionals-three-types pages.
A note on word order in subordinate clauses
Subordinate clauses in French follow the same SVO word order as main clauses. Unlike German (which moves the verb to the end of subordinate clauses), French keeps verb position stable.
Je sais que Pierre mange une pomme.
I know that Pierre is eating an apple. (SVO inside the que-clause)
Quand Pierre arrivera, on commencera.
When Pierre arrives, we'll start.
The only place where French subordinate clauses adopt unusual word order is in literary inversion after certain conjunctions like aussi, à peine, peut-être, but this is a stylistic flourish, not a grammatical requirement.
Common Mistakes
❌ Si je serais riche, je voyagerais.
Wrong — never use the conditional in the si-clause itself.
✅ Si j'étais riche, je voyagerais.
If I were rich, I would travel.
❌ Je veux qu'il vient.
Wrong — vouloir que requires the subjunctive (vienne), not the indicative.
✅ Je veux qu'il vienne.
I want him to come.
❌ L'homme que parle est mon père.
Wrong — qui (subject of relative clause), not que.
✅ L'homme qui parle est mon père.
The man who is speaking is my father.
❌ Bien qu'il pleut, je sors.
Wrong — bien que requires the subjunctive (pleuve), not the indicative.
✅ Bien qu'il pleuve, je sors.
Although it's raining, I'm going out.
❌ Je sais qu'il vienne.
Wrong — savoir que takes the indicative (vient), not the subjunctive.
✅ Je sais qu'il vient.
I know that he's coming.
❓ Pars avant qu'il arrive.
Looks like indicative, but avant que requires the subjunctive — and the 3rd-person singular subjunctive of arriver happens to be identical in form to the indicative.
✅ Pars avant qu'il arrive.
Leave before he arrives. (arrive here is subjunctive — confirmed by parallel forms like avant qu'il vienne or avant qu'il fasse, where the subjunctive is visibly distinct)
Key Takeaways
A French subordinate clause depends on a main clause and is introduced by a subordinator: que for completive clauses, relative pronouns (qui, que, dont, où) for relative clauses, and a wide array of adverbial conjunctions (quand, parce que, si, pour que, bien que) for adverbial clauses. The defining grammatical decision in any subordinate clause is which mood the verb takes: indicative for assertions and known facts (je sais qu'il vient), subjunctive for wishes, doubts, emotions, and after specific conjunctions (je veux qu'il vienne, bien qu'il pleuve), conditional for the main clause of si-hypotheticals (si j'étais riche, je voyagerais — never si + conditional). French subordinate clauses keep SVO word order and can be nested deeply, with each layer making its own mood choice. For deep treatment of relative pronouns, see sentences/relative-clauses-restrictive-vs-non; for the full subjunctive trigger list, see the verbs/subjunctive cluster; for the hypothetical patterns, see complex/conditional-sentences-overview; and for a master table of all clause types and mood requirements, see complex/clauses-overview-table.
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